A
mulch of pine needles provides an airy blanket that conserves
moisture, retards weeds, and provides nutrients to the rhododendrons.
These needles are from an eastern white pine (left in picture).

Many people
spend a great deal of time watering, fertilizing, and weeding
their rhododendrons. There is a much easier way, and it is healthier
for the plants--natural mulch. In The Anderson Garden, we don't
use any fertilizer, don't water established plants, and do a minimum
of weeding. While it is not possible to totally avoid these chores
in all climates and soils, the tasks can be greatly reduced.

Mulch is also
good for the environment. Besides saving water resources and eliminating
the need for chemical fertilizers and herbicides, it reduces runoff
and acts as a first filter for the ground water. Mulch allows
the gardener to make good use of a resource many people either
burn or send to the landfill.

Not all mulches
are the same. While purchased products, such as ground bark, will
do the job, a much easier, cheaper, and more effective way to
mulch is to plant the right companion trees for rhododendrons.
But careful selection is important.

Many trees
have invasive roots that rob shrubs of moisture and nutrients,
defeating the purpose of the mulch they produce. And many trees
produce a heavy mat of leaves or needles that solidifies as it
dries. These same trees often create a canopy that is too dense
for open shade loving rhododnedrons.

The best companion
trees we have found are pines (above) and oaks (below). Both send
down deep tap roots rather than spreading surface roots. We have
rhododnedrons that have completely encircled pines and oaks as
they have grown over the years, while firs and maples have killed
a circle of plants around them (even grass.) These deep roots
also absorb trace minerals from deep within the subsoil, and then
deposit them on the surface in their leaves and needles. Oaks
have the additional benefit of adding tannin to the soil around
the acid-loving rhododendrons.

Pines and
oaks provide a good filtered shade, especially if the lower branches
are removed. They offer protection from the wind, but allow free
circulation of air to reduce the threat of powery mildew. The
mulch they annually provide is loose, letting air and moisture
to penetrate, but blocking out light and and moderating ground
temperature. (Sometimes you might need to plant trees that are
not ideal rhododendron companions if there are overriding reasons.
We planted several Douglas firs as a break against the notorious
Enumclaw east wind, and a number of Japanese maples because their
colors and shapes complement the other plants so well. Other competitive
trees are single specimems, such as dawn redwood, sequoia, and
sweet gum. They produce acceptabale mulch, but need plenty of
space around them.)

Oak
leaves provide the same benefits as pine needes, and add acid
to the soil. Some also have beautiful fall color.

Another good
source of mulch is pruning. Everything we prune under two inches becomes
mulch for the beds. Rhododendron trimmings are especially valuable,
because they can return much of the potassium back to the roots
of these potassium-hungry plants. But prunings from trees, hedges,
fruit and berry stock, all have something to add to the soil.

We had a shredder
but got rid of it. It is almost as fast to clip the pieces into
six to eight inch lengths at the same time you are pruning, and
the plants like the coarser mulch. It probably is just as fast
if you consider the time for buying gas, replacing belts, sharpening
blades, and doing other upkeep on these high maintenance machines.
Equally important, they are so loud they prevent your neighbors
from enjoying their gardens while you are shredding away.

Mulch makes
for a win-win-win situation. It makes life easier for the gardener,
benefits the environment, and keeps the rhododendrons happy.